Re: 3D OpenGL applications eat CPU ressources

[Alex Deucher <alexdeucher@gmail.com>]

On Sun, Feb 7, 2010 at 12:18 PM, Émeric Maschino
<emeric.maschino@gmail.com> wrote:
> 2010/2/7 Stephane Marchesin <stephane.marchesin@gmail.com>:
>> From what I recall, all the ia64 AGP chipsets (well the zx1 and the
>> 460) have to be run:
>> - without side band adressing
>> - without fast writes
>> - at 4x speed
>> otherwise they're unstable.
>>
>> I think by default agpgart puts them at AGP 1x with fast writes...
>
> Without /etc/X11/xorg.conf, AGP is configured as follows:
> - 2x rate
> - fast writes are disabled.
>
> Adding /etc/X11/xorg.conf in order to manually set AGP rate at 4x
> didn't help. Running glxgears triggers GPU lockup slightly faster than
> at 2x or 1x rate (well, GPU lockup appears in less than 1 sec. vs.
> ~2-3 sec. at slower rates).
>
> I've no idea about sideband addressing. Is there a way to check
> whether it's enabled or not? And is there a way to disable it?
>
> Just for completeness, Chapter 8.2.3 (AGP Registers) of HP zx1 ioa
> External Reference Specification
> (http://ftp.parisc-linux.org/docs/chips/zx1-ioa-mercury_ers.pdf) says
> that zx1 chipset supports:
> - AGP 1x, 2x and 4x data rate
> - fast writes for PIO transactions
> - sideband addressing.

Does AGP work at all on ia64?  I know on some alphas there were cache
coherency issues or something like that that more or less prevented
AGP from be usable at all.  It was mostly there to accommodate AGP
form factor cards.

Alex

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